Curious whale in Wellington Harbour delays berthing of Interislander ferry and postpones capital's Matariki fireworks

A curious southern right whale in Wellington Harbour today has delayed an Interislander ferry and forced the cancellation of the capital's Matariki fireworks display.

Footage posted to Twitter by @GwennRJ shows the large ferry making its way slowly into the harbour with its horn blaring in warning to the whale which is watching on from a safe distance.

A tweet posted by KiwiRail seemed to be very understanding of the unique situation.

"Our Interislander crew is watching Wellington's whale as closely as the rest of the country! Kaiarahi had to delay berthing this afternoon as we didn’t want to put our visitor at risk. We hope our passengers understood (and enjoyed the view)," the tweet reads.

The whale has caused the Wellington City Council to postpone a planned Matariki fireworks display until next weekend for the safety of the whale and people in the harbour.

"The advice we've received is that the noise from the fireworks is unlikely to cause harm to the whale but that it could cause it to act unpredictably if it is in the vicinity," says Wellington's acting mayor Jill Day.

"We don't want anyone in boats or kayaks on the water, in the dark, to come off second-best if the whale breaches among them.

"We also don’t want the whale to be injured in any contact with a vessel."

It's the first recorded sighting of a southern right whale in the capital for eight years.